#include "bytebuffer.h"

#include <algorithm>
#include <cassert>
#include <cstring>

#include "byteorder.h"

namespace base {

	static const int DEFAULT_SIZE = 4096;

	ByteBuffer::ByteBuffer() {
		Construct(NULL, DEFAULT_SIZE, ORDER_NETWORK);
	}

	ByteBuffer::ByteBuffer(ByteOrder byte_order) {
		Construct(NULL, DEFAULT_SIZE, byte_order);
	}

	ByteBuffer::ByteBuffer(const char* bytes, size_t len) {
		Construct(bytes, len, ORDER_NETWORK);
	}

	ByteBuffer::ByteBuffer(const char* bytes, size_t len, ByteOrder byte_order) {
		Construct(bytes, len, byte_order);
	}

	ByteBuffer::ByteBuffer(const char* bytes) {
		Construct(bytes, strlen(bytes), ORDER_NETWORK);
	}

	void ByteBuffer::Construct(const char* bytes, size_t len,
		ByteOrder byte_order) {
			version_ = 0;
			start_ = 0;
			size_ = len;
			byte_order_ = byte_order;
			bytes_ = new char[size_];

			if (bytes) {
				end_ = len;
				memcpy(bytes_, bytes, end_);
			} else {
				end_ = 0;
			}
	}

	ByteBuffer::~ByteBuffer() {
		delete[] bytes_;
	}

	bool ByteBuffer::ReadUInt8(uint8* val) {
		if (!val) return false;

		return ReadBytes(reinterpret_cast<char*>(val), 1);
	}

	bool ByteBuffer::ReadUInt16(uint16* val) {
		if (!val) return false;

		uint16 v;
		if (!ReadBytes(reinterpret_cast<char*>(&v), 2)) {
			return false;
		} else {
			*val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost16(v) : v;
			return true;
		}
	}

	bool ByteBuffer::ReadUInt24(uint32* val) {
		if (!val) return false;

		uint32 v = 0;
		char* read_into = reinterpret_cast<char*>(&v);
		if (byte_order_ == ORDER_NETWORK || IsHostBigEndian()) {
			++read_into;
		}

		if (!ReadBytes(read_into, 3)) {
			return false;
		} else {
			*val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost32(v) : v;
			return true;
		}
	}

	bool ByteBuffer::ReadUInt32(uint32* val) {
		if (!val) return false;

		uint32 v;
		if (!ReadBytes(reinterpret_cast<char*>(&v), 4)) {
			return false;
		} else {
			*val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost32(v) : v;
			return true;
		}
	}

	bool ByteBuffer::ReadUInt64(uint64* val) {
		if (!val) return false;

		uint64 v;
		if (!ReadBytes(reinterpret_cast<char*>(&v), 8)) {
			return false;
		} else {
			*val = (byte_order_ == ORDER_NETWORK) ? NetworkToHost64(v) : v;
			return true;
		}
	}

	bool ByteBuffer::ReadString(std::string* val, size_t len) {
		if (!val) return false;

		if (len > Length()) {
			return false;
		} else {
			val->append(bytes_ + start_, len);
			start_ += len;
			return true;
		}
	}

	bool ByteBuffer::ReadBytes(char* val, size_t len) {
		if (len > Length()) {
			return false;
		} else {
			memcpy(val, bytes_ + start_, len);
			start_ += len;
			return true;
		}
	}

	void ByteBuffer::WriteUInt8(uint8 val) {
		WriteBytes(reinterpret_cast<const char*>(&val), 1);
	}

	void ByteBuffer::WriteUInt16(uint16 val) {
		uint16 v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork16(val) : val;
		WriteBytes(reinterpret_cast<const char*>(&v), 2);
	}

	void ByteBuffer::WriteUInt24(uint32 val) {
		uint32 v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork32(val) : val;
		char* start = reinterpret_cast<char*>(&v);
		if (byte_order_ == ORDER_NETWORK || IsHostBigEndian()) {
			++start;
		}
		WriteBytes(start, 3);
	}

	void ByteBuffer::WriteUInt32(uint32 val) {
		uint32 v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork32(val) : val;
		WriteBytes(reinterpret_cast<const char*>(&v), 4);
	}

	void ByteBuffer::WriteUInt64(uint64 val) {
		uint64 v = (byte_order_ == ORDER_NETWORK) ? HostToNetwork64(val) : val;
		WriteBytes(reinterpret_cast<const char*>(&v), 8);
	}

	void ByteBuffer::WriteString(const std::string& val) {
		WriteBytes(val.c_str(), val.size());
	}

	void ByteBuffer::WriteBytes(const char* val, size_t len) {
		memcpy(ReserveWriteBuffer(len), val, len);
	}

	char* ByteBuffer::ReserveWriteBuffer(size_t len) {
		if (Length() + len > Capacity())
			Resize(Length() + len);

		char* start = bytes_ + end_;
		end_ += len;
		return start;
	}

	void ByteBuffer::Resize(size_t size) {
		size_t len = _min(end_ - start_, size);
		if (size <= size_) {
			// Don't reallocate, just move data backwards
			memmove(bytes_, bytes_ + start_, len);
		} else {
			// Reallocate a larger buffer.
			size_ = _max(size, 3 * size_ / 2);
			char* new_bytes = new char[size_];
			memcpy(new_bytes, bytes_ + start_, len);
			delete [] bytes_;
			bytes_ = new_bytes;
		}
		start_ = 0;
		end_ = len;
		++version_;
	}

	bool ByteBuffer::Consume(size_t size) {
		if (size > Length())
			return false;
		start_ += size;
		return true;
	}

	ByteBuffer::ReadPosition ByteBuffer::GetReadPosition() const {
		return ReadPosition(start_, version_);
	}

	bool ByteBuffer::SetReadPosition(const ReadPosition &position) {
		if (position.version_ != version_) {
			return false;
		}
		start_ = position.start_;
		return true;
	}

	void ByteBuffer::Clear() {
		memset(bytes_, 0, size_);
		start_ = end_ = 0;
		++version_;
	}

}  // namespace base
